FIG. 1 shows the back of a conventional semi-trailer or cargo container 10 or other similar enclosed body, preferably in the form of an International Standards Organization (ISO) container, domestic container or semi-trailer, having a pair of doors 12 and 14, hinged along their outer edges at 16 and 18 to opposite vertical sides 20 and 22 of door frame or opening 24. Thus, doors 12 and 14 are mounted for relative rotation in opposite directions around sides 20 and 22 between a closed position as shown in FIG. 1, and an open position. When either or both doors 12 and 14 are open, ready access is provided through door opening 24 to load or unload cargo into or out of the trailer or container 10.
When doors 12 and 14 are closed, an overlapping tab (door retainer) which can be internal or external to the doors, can be used. In use, door 12 is closed first and thereafter door 14 is closed to overlap and hold door 12 closed. Typically, an overlapping tab (door retainer) which is external to the doors can be used to overlap door 12. Subsequently, door 14 is typically opened first before door 12 can be rotated to the open position.
Carried by each door is a conventional closure assembly of any number of axially rotatable rods 30, suitably journaled in upper and lower brackets 32 and 34 on the door and provided with a handle 36. The upper and lower ends of the rod 30 engage with cam members 38 and 40 and bring the door to a fully closed position as the handle 36 and attached rod 30 are manually rotated to the position in FIG. 1. When in this position, a padlock or the like can be used to keep handle 36 and attached rod 30 in the closed position, as shown.
Accordingly, the manually operable closure means (rod 30, brackets 32 and 34, handles 36 and cam members 38 and 40) are located on the exterior of the container 10 where they are readily accessible by authorized and unauthorized workers and drivers, as well as would be thieves intent on stealing products and goods which may be contained in the semi-trailers and similar bodies and like enclosures. Previously, the security for these trailers, ISO containers, domestic containers and the like has been quite poor, usually consisting of a padlock and/or seal having an exposed link which can be cut by bolt cutters or equivalent tools. Thus, semi-trailers, containers and trucks left unattended for any length of time, as over night in truck terminals, intermodal terminals and freight yards, on shipping docks and piggy-back railroad cars, or at industrial or commercial loading areas (and during transit), are vulnerable to thievery and pilferage.
The problem of vulnerability of externally located closure means is minimized by the present invention, through the employment of a retrofitable or factory installed security system adapted to be located within a container, where it is not accessible to a would be thief or opportunist.
There is a need for a security system adapted to be located within a container, where it is not accessible to a would be thief or opportunist.
There is an ever demanding requirement for improved security systems for cargo loading doors and enclosures for the worldwide transportation industry.
Solenoid actuated locking devices are known and find numerous applications. An example is the locking of doors. In such an application, a locking mechanism is adapted to a solenoid which is secured either to the door or the door jamb. Selective energization of the solenoid drives a lock actuator for effecting actuation of the locking mechanism and securely locking the door. The components of the solenoid locking system may be completely contained within the door system to resist tampering.
One consideration when employing a solenoid locking system is the source of energy for driving the solenoid device, typically electrical energy. Where the solenoid locking device is contained within doors of a building, obtaining and providing a sufficient source of electrical energy is not a problem. The system is simply tied into the building electrical system. However, a sufficient source of electrical energy may not always be readily available.
Because of its superior locking capability, solenoid locking devices have been adapted to cargo containers, storage containers, over-the-road truck trailers and other similar type cargo carrying containers. In some instances, there is a source of electrical energy nearby, such as from the electrical system of the tractor. However, often the container, storage container, trailer or similar enclosure, will be remotely located from a source of electrical energy. To provide electrical energy for actuating the solenoid locking device, the container is provided with a battery for supplying electrical energy to the solenoid.
One disadvantage of using a battery as a source of electrical energy for the solenoid is its limited supply of energy. Unless care is taken to preserve battery energy the battery may be discharged to a state in which it will no longer provide sufficient electrical energy to operate the solenoid. Another disadvantage of battery systems is the limited electrical potential of the battery. Unless the battery contains a large number of cells, and hence is a very large battery, its electrical potential (voltage) is relatively low limiting the size of the solenoid which may be effectively driven by the battery. Use of a smaller solenoid dictates use of smaller locking components, and hence, provides less security. Larger batteries do not provide a sufficient solution because of their size and cost.
Unlike buildings which to some degree allow for protecting the solenoid locking device from the environment, the device incorporated into a shipping container will experience large changes in environmental conditions. Thus, the solenoid actuated locking device fitted to a container must further adapt and adjust its operating characteristics in response to changes in temperature.
Therefore, there is a need for a solenoid locking device which may be operated using a battery source of energy yet which provides substantial electrical potential for actuating the solenoid. The device must also compensate for varying operating conditions as a result of changing environmental conditions and preserve battery energy.